读江苏省第五次和第六次全国人口普查数据统计表及人口年龄结构变化图，完成下列各题。

已知某几何体的三视图如图，其中正(主)视图中半圆的半径为1，则该几何体的体积为(     )
 

阅读短文，选择正确的答案。

    I am seven. I go to school every day. Classes start at eight o'clock. In the morning. I have Chinese, Art and Maths. I have English and P.E. in the afternoon. I get home at half past four. I watch TV at home. I have a good friend, Xiaotian. He sleeps at school. He goes to bed at nine. I go to bed at half past nine.